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Encryption Security

Crack A "Numbers" Station 210

boss soul writes: "On Friday, NPR did an excellent story on those infamous 'Numbers Stations' that broadcast on shortwave radio. Since the 1950s, these stations have been broadcasting nothing but an unidentified human voice reading a string of numbers. Though most people believe that these broadcasts are used by intelligence agencies to communicate with their agents abroad, there has never been any way to confirm this ... until now! The makers of "The Conet Project" (a four-CD set of numbers-station recordings) have thrown down the proverbial gauntlet and announced a series of "cryptographic challenges" -- the object of which is to crack an actual numbers station broadcast. Dust off your Crypto caps, everyone -- I want to see a slashdotter win this one! "
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Crack a "Numbers" Station

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  • The previous run of this story is ref'd, but the discussion did center around use of codes on insecure channels during WWII. A good book, for the interested party, is Between Silk and Cyanide, by Leo Marks (ISBN 0684864223).

    I'd have to echo the pessimistic sentiments of others in this discussion, though, and state that there's probably not a lot of hope in 'cracking' these transmissions, given that we have no knowledge of their origin or purpose.

  • These are the digits of PI computed with Srinivasa Ramanujan's famous series, written backwards and concatenated for successive terms in the series!

    There is no code.
  • I'm just wondering how many spy agencies around the world have ~50 years of contiguous recordings stacked up for each station.

    --
  • How about using the numbers from these stations as a one-time pad for encrypting unrelated material? Hell, they're out there, why not use them? :)
  • I can see it now. Half a dozen GRU (or KGB, I suppose) in an underground bunker in the midwest, huddled over a transmitter, still sending intelligence information, blind to the fact that the Soviet Union has fallen and the Cold War is theoretically over. Just watch, when someone decodes this stuff, it's going to turn out to be "FROM NEVADA 314 STOP TO MOSCOW STOP CURRENT AMERICAN PROPOGANDA IS THAT MOTHERLAND HAS COLLAPSED STOP PLEASE SEND MORE VODKA STOP" or some such.
    Nothing against Russians, mind, i'm proud to sort of be one, but this would make such a great spy novel.
    ===
    -J
  • Given the fact that, although the encoding is random, there is a 1 to 1 relationship between the encoded character and a number, I think it may be possible to crack a one-time pad based on the frequency of numbers in the encoded message.

    How, I'm not exactly sure, but it does seem like you can at least get started on these.
  • nope, just screwing :)
  • Comment removed based on user account deletion
  • Actually, no. The story is now archived and always displayed with the highest ranked comments first.
  • ...at work Friday and was transfixed; it's part of NPR's "Lost and Found Sounds" series, and this show, like the series generally, was fabulous.

    You owe it to yourself to listen to it: www.npr.org, drop down "Choose a program" and select "All Things Considered" and then "Latest Show" - which this still is, given that ATC is only on on weekdays.

    I just listened to it again (one of the *crappiest* RealAudio streams I've come across lately, BTW, but then it was 20 (!) hops out...) and it's pretty cool.

    Pretty eerie stuff..

    The best one is the "Buzzer" - been up for over twenty years on the same frequency, apparently, and only run one number series *once* in that time - as far as anyone knows...

    Creepy..

    t_t_b
    --

  • ... not as hard as crackin RC-64, but hard nevertheless. Think about it -- why are those transmitted through human voice? If the recipient always had powerful and up to date computing equipment, it'd be much better to have it transmitted manually. Then the bandwidth of such stuff is very bad. Sooo ... to begin with we might have to think of the uses of the stuff.

    Then ... even though they're emitting constantly, they might not actually be transmitting info all the time. So much of the stuff will be complete garbage ...

  • I only showed the first step of the process, converting a message text into five digit code groups. If that was transmitted, it could be cracked by a cryptanalyst in minutes. The step that makes it secure is the one time pad. Using the previous message:

    73758 40855 40850 (encoded plaintext)
    64270 19371 16214 (one time pad)
    37928 59126 56064 (encrypted message)

    The encoded plaintext is added to the one time pad with modulo 10 arithmetic, a single digit at a time. The result is the encrypted message, ready for transmission. The recipient of the message reverses the process by subtracting the one time pad from the received message, again with modulo 10 arithmetic, a single digit at a time.

    37928 59126 56064 (encrypted message)
    64270 19371 16214 (one time pad)
    73758 40855 40850 (encoded plaintext)

    Assuming the one time pad was properly generated from a true random number source, there are no statistical anomalies in the encrypted message that could aid a cryptanalyst.

  • by swinge ( 176850 ) on Saturday May 27, 2000 @01:13PM (#1042856)
    they used to transmit "data" when there was no message, but now they sending downloads of Dr. Dre and Metallica to agents in the field who have been thrown off of Napster

    Has anybody checked that the 4-cd set isn't just audio? wouldn't that been a good joke to pull on the crypto community ;)

  • I posted earlier about how this must be a bunch of lost Soviet spies, but I came up with soehting that makes even more sense.
    See, I was in the library today, doing some research on the ISS. I found an article in April 2000 Popular Mechanics, and after skimming it, I turned out of curiosity to the magazine's cover story: The KGB plot to bring america to it's knees. Apparently KGB (and/or GRU; no-one is quite sure) agents were involved in an elaborate scheme to take advantage of the Canadian and Mexican borders and plant explosives in military bases, dams, power stations, etc, up to and including the power source for New York city. The idea was that massive power outages, especially in NYC, would cause Americans to overthrow their government.
    So, this is clearly part of that op. The russians set up a bunch agents to read random numbers over america's radio stations, causing the populace to revolt against the FCC. Only they got the frequencies wrong. Or something.
    See, it all makes sense!

    I think I need to go lie down...
    ===
    -J
  • There is NOT a one to one relationship between encoded "numbers" and characters in a one time pad encrypted message. In fact, there is no relationship at all, that is why OTP is so secure. OTP encryption uses a random key that is exactly as long as the entire message, then the key and the message are "convoluted" together to create an essentially random (as random as your key) message which is essentially uncrackable without the key.

    OTP encryption has been cracked before but ONLY when the same key was used more than once.

  • Also you have to encrypt using their PGP key, not yours, so you aren't 'proving your identity'

    Unless you use the encrypt/digital sign function.

  • No no no. How about they're reading out the DVD CSS keys?

  • by ChrisSmolinski ( 193270 ) on Saturday May 27, 2000 @01:25PM (#1042861)
    As you can probably guess, most stations use a synthesized voice. In the past, some stations (pre computer days) used either spliced tapes, or an interesting contraption that was a rotating drum with several tracks, one for each number or word spoken. It turned, and the correct track was read to play a digit (the phone company used this as well to handle messages when a number changed).

    Some still do "live" transmissions, the Bored Man and Babbler stations come to mind.

    Visit http://www.spynumbers.com for more information about spy numbers stations.

    I have a CDROM out, with about ten hours of recordings, and lots of information, all organized as a web site, so it's cross platform.

  • I think it is. If this is indeed an intelligence agency sending messages to agents in the field, how on Earth would be able to know what does the message mean. Maybe 05765 means a specific embassy, a place where you have to take a photography, a street, the name of a government official. There are 100,000 posible references to places or people we don't know. This is the same technique used by the mob (as shown in movies, that is) to communicate to people in jail and by many people using numbers-only pagers; it's extremely effective because it's related to concrete actions (911=call Mom!) we don't know anything about. If this is the case, there's no way we're going to solve this.

  • by Bowie J. Poag ( 16898 ) on Saturday May 27, 2000 @09:22AM (#1042863) Homepage


    As a little birthday gift to myself, I picked up a fairly high-end handheld digital shortwave radio like a week ago. Its an amazing little device, when you think about it.. In your hands you hold a box capable of opening a window into the communications of every technologically advanced culture on the planet, runs on three AA batteries, and will run forever if you take care of it. Not a bad deal for $219.00 :)

    That being said, here's a little something about numbers stations: Alot of them have already been linked directly to intelligence agencies, so, thats not a rumor anymore. Its a fact. Our on CIA, and Israel's Mossad are among a growing list of agencies known to be running numbers stations, as the broadcast source has been proven to be on land owned by these agencies.

    On a totally different not, my own father ran crypto for the Navy (even had clearance at the Pentagon for a short time!) for a few years during the mid-late 1950's. During his stint in the Navy, he was stationed in Adak, Alaska where he and and a bunch of other guys jobs' were to monitor Russian shortwave radio traffic..mostly stuff in the Bering Strait, and from stations in and around the Kamchatka. To this day he can copy morse code by hand fast as fuck. :) A few weeks ago, I played some of the "numbers" station recordings for him, and he says he has never heard them before. I told them theyre linked with foreign intelligence agencies and his response was "Not surprising. Theyre all over the dial." :)

    Whatever that means. :)



    Bowie J. Poag
  • The whole encryption scheme which numbers stations use is uncrackable. Known as a "One time pad" the scheme can only be used once, otherwise, both parties risk the message being intercepted by a thrid hostile party. It's a super simple encryption method. I write out the alphabet several times and then randomanly write down numbers [0..9][0..9][0..9] next to the letters and make 1 copy of this sheet and give it to my agents. Then when I need to communicate with them I encode my message using these numbers.
  • by Detritus ( 11846 ) on Saturday May 27, 2000 @09:30AM (#1042865) Homepage
    The U.S. Air Force Strategic Air Command had something similar with their "Sky King" broadcasts on the high frequency bands. They sent out coded messages at regular intervals using SSB (single sideband) voice. This was one of the systems for sending EAMs (emergency action messages) to SAC's nuclear armed bombers. When listening, you never knew if the message was "testing" or "nuke Moscow".
  • There are 5 different messages to crack :

    1.E3 (The Lincolnshire Poacher) [ibmpcug.co.uk]
    2.E5 (CIA Counting Station) [ibmpcug.co.uk]
    3.E22 (New Station!) [ibmpcug.co.uk]
    4.E10 (Phonetic Alphabet Station) [ibmpcug.co.uk]
    5.G2 (The Swedish Rhapsody) [ibmpcug.co.uk]

    And (look at the last line) " The Prize for the first person to email us a deciphered text along with the method employed in the crack will be an ancient Gold Roman coin. The Judges decision is final. "

    Also you have to encrypt using their PGP key, not yours, so you aren't 'proving your identity', just (hopefully) making sure nobody besides them can read your email. However that doesn't mean the NSA/Men In Black won't say hello if you crack it.

  • When confronting KGB, agent must throw >18 2D20 to save vs. unusual persuasion. Use freq. 376.125 for throw.


    When captured by KGB, agent must throw >22% to save vs. truth serum. Use freq 377.375 for percentile digits.


    Chance encounters with gelatinous cube, cube appears >19 2D20. If east of Iron Curtain, use freq. 272.5 for throw. If west of IC, use 377.75.

  • I bet the Real Steve Woston [mnc.co.za] could do it.

  • Love that sig :)

    Notice:"The price of tea in china has changed, Windows will now restart so this change can take effect."
    ___

  • One possible theory not mentioned here is that the OTP is actually a book: like a well-known piece of literature that is easy to get. Then the cypher will be the page number, line(or paragraph) number, and a word number smashed together. To decode you need to know which book and which print (to keep pages in sync) or possibly go with print-independent numbers: chapter/paragraph/word combination. This possibility was mentioned in one of the Russian cold-war era spy movies.
  • They read them SLOW enough that a computer SHOULD be able to process them with good accuracy. The voices are very clear, also. Whatever it is, its important stuff.
  • During WW2 when the atomic bomb was being built, Truman wasn't told about it until he needed to know. Remember Rosevelt was president first and then Truman.

    Point being, they wouldn't necessarily tell you. :)

    Shawn
  • There are two very important things that the above argument (that the challenge is unwinnable because the cryptographic messages is context-based and we don't know the context) doesn't seem to take into consideration. First, that if the numbers are, in fact, cryptographic messages, they were designed to be unencoded by someone somewhere. Second, the person unencoding the message probably hasn't had a computer transcribing the numbers for auto-decryption for the duration that the messages have been transmitted.

    Bottom line: for any message, not only must you consider the context and content, you must also consider the intended receiver and the medium.

    Aside: (Interestingly, I made this same argument the thesis for a class on German Existentialism, where I attempted to explain Heidegger's views on art. It was entitled "Dasein and Kunst".)

    ::Colz Grigor
    --

  • by Anonymous Coward
    why transmit the numbers using speech? It seems like it would be a hell of a lot easier to modulate them (like a modem) into a tone. That way you don't have to have a person (or voice-recognition software) who can fuck up on the other end. Unless it's going out to a bunch of spooks listening to their shortwave radios in the boonies with a pad and paper, in which case (1) it's human-crackable or (2) there are a bunch of decoders or one-time pads floating around just waiting to be discovered.
  • From http://www.nsa.gov/docs/venona/monographs/monograp h-4.html:

    The KGB communications between Mexico City and Moscow during 1943-46 are a particularly rich historical trove, showing the elaborate plans to free from prison a man using the covername GNOME, who had murdered Trotsky in Mexico City in 1940.

    Hmn... GNOME... Mexico... Do I see a pattern?

    Many of these messages concern the GNOME affair and indicate that the KGB had two plans to
    facilitate his release: a combat operation, to spring him by force, or an effort to use influence.

    So, that's why it's spreading so fast. It's a KGB conspiracy!

    GNOME's mother's presence in Mexico is complicating the case

    That must refer to miguel (mother, father, what's the difference?)

    The Fishers were clearly important KGB officers, operating under instructions from Beria. Their goal was to take over the GNOME affair, to support operations in the U.S., maybe even for atomic bomb espionage. 1

    That definately sounds like helixcode

    I smell a conspiracy!

  • It's 13375p33k!
  • All one has to do is realize that the pads numbers can not be purely random.
    Why can't they be? Sure, it's possible that they'd use an algorithm out of laziness, but there's no reason why they couldn't roll dice, or even use a "quantum noise" number generator.
  • These codes are not ment for someone with a code book. If you are a spy and possably undersurvalance from whatever organization your spying on. You do not want a big black book of numbers and letters sitting somewhere that someone could find if they searched you or your home. More than likley these numbers correspond in some slightly obfuscated form to an everyday object. Maybe to the Polish edition of war and peace. maybe to the moscow times. I seriously doubt that these numbers correspond to an actual code book though. -Rich N
  • I strongly suggest you take a look at recent /. articles.

    Doing something impossible twice is pretty impressive, 'specially if the second time they do it it's even worse than the first. :) So this crypto stuff - quite possible. :)

    -------
    CAIMLAS


  • The problem with eliminating "disinformation" stations is this: how would you know which ones are broadcasting truely random information and which are not? You propose statistical tests on the series of numbers. We would assume that these disinformation stations would be using cryptographically secure random number generators. If so, "cracking" these would be just as hard as cracking the real algorithm. In fact, any cryptographically secure random number generator can be converted trivially to stream cipher.
  • about your .sig, donkey kong was supposed to be called monkey kong, but due to a bad phone line, it accidently became donkey kong.

    Mikael Jacobson
  • by Penrif ( 33473 ) on Saturday May 27, 2000 @08:46AM (#1042882) Homepage
    That has got to be one of the worst jobs ever, reading a very long string of numbers... I can only assume they recorded 'em though,

    "One Five Seven...no Two...sorry. Eight"

  • Close, very close. I've spent a few years in a hole in the ground which was also operated by SAC, even got a few blue jumpsuits with nifty patches. No Hollywood or pseudo-macho here: It doesn't matter how much computing power is gathered, that is not the way to crack this kind of communication. More than likely there are one-time key methods being used and pros don't use methods which involve consistent application of keys for this type of encryption. This isn't a stream-encryption like would be used in, say, a voice scrambler. The idea that there is some form of one-to-one character relationship is ludicrous. (I have to be very careful how I state this...) Pick up any elementary-level book on codes and secret writing and there's a good likelihood you'll see an example of numbered word dictionaries. 0001 = battalion, 0002 = dawn, etc. You'll also see examples of combining encryption methods within a single message. Put another way, if the final scene was missing from the Citizen Kane movie, all the computers in the world would not be able to deduce demonstratively that Rosebud was the sled. Attempting to find a pattern and then somehow use that to "crack" this form of communication is an absolute waste of time, period. There are just too many variables. Now, if a team used radio direction finding equipment and was able to stalk, trap, and interrogate people and somehow trace other personal connections without alerting the Borg (whoever they may be), there might be a shot. But it ain't going to happen in this reality.
  • OK, so who's thinking "COMSTOCK"? ;-)
  • ...it's just a language with really long words. Probably the damn Eskimos.

  • by Seumas ( 6865 ) on Saturday May 27, 2000 @08:48AM (#1042887)
    Distributed.net...

    It would seem that there must somehow be a way to implement distribute.net into solving this (if there is any solution). Why work against each other if we can all work together and nail this?

    I'm not a crytpo-expert, but my guess is that you would need to use a wide variety of formulaes to even ever discern that there is a pattern, let alone what the patterns signify. But the formulae could be well-tested on a mass-scale via distributed.net and then once a group of likely candidates is discovered, attack them on a massive scale and see if anything hits.

    But like I say, I'm not an expert whatsoever. This just sounds like a way to approach it. But, unlike RC5 and DSS, this doesn't have a known answer hiding somewhere with any manner of known mathamatical processes of resolution, so brute-force would be out of the question, no? Unless there is a way to massively process *methods* and *formulaes* to see if they're even appropriate to ever do brute-force decryption along side.
    ---
    icq:2057699
    seumas.com

  • by sesquiped ( 40687 ) on Saturday May 27, 2000 @02:02PM (#1042888)
    2) A one-time pad usually encodes phrases, not letters or single words. A complex one can have multiple phrases available from which one can construct a complete message, ie 48 = "meet me," 47 = "at the courthouse steps," 97 = "at phillip's house," and so on. Both the numbers and the phrases can be chosen arbitrarily, and can be changed every week or even every day.

    No!

    That's a codebook, not a one-time pad. If you'll notice, the frequencies of different digit pairs (using your example) will likely be different. That's no good. A one-time pad is a long string of true random numbers. They would most often be combined with the message with a simple XOR algorithm, although something else might be more appropriate when using pencil and paper. The point of a "one-time" pad is that the same numbers are never used more than once, hence the name one-time. It's not changed once a day or week, it's destroyed immediatelly after use!
  • by Seumas ( 6865 ) on Saturday May 27, 2000 @08:48AM (#1042889)
    ...As read by James Earl Jones... ;)
    ---
    icq:2057699
    seumas.com
  • Still, now after the CSS debacle, I'm always inclined to hold out the possibility that someone designing the system has screwed up royally. And even though the obvious thing is to assume that nobody will figure any of these out -- the possibility is still there, that somebody's code is just fucked up.

    Let's say, you're making a cyper, and the restriction is that your spies can't have any codebook of any kind on their body to be kept around as evidence. Say, for example, that your spies can know what time the secret message is coming, but they can't just sit and listen all day. I'm trying to think through, given restrictions like this, what the encryption would look like. Is there Phd-type research on exactly this kind of thing?
  • There were ciphers in the 1950s (probably quite crackable now) and they may have used a OTP in the past.

    However there's no reason they haven't changed things and now use a computerised cipher -- after all, with encrypted data, we'd never notice a switch between two good ciphers (without cracking it, anyway).

    I somehow doubt the exact same set-up has been running 50 years.
  • And this doesn't even need to be a real, cryptographically random codebook. It could be Webster's dictionary, any phone book, "Programming Perl," (god forbid) or "The Catcher in the Rye" (any edition). The method used here would be to quote a page number, which would correspond to the first (or any other previously-agreed upon) word on that page. Another fringe benefit of this method is that having a copy of "The Stand" doesn't necessarily mean you are a spy, while having a cryptographically random codebook would be awfully hard to explain.

    The task of being _able_ to search the entire world's printed matter (in each particular edition) for the past thousand years or so is in itself a massive undertaking. To be able to use such a database in a meaningful way would also be very very difficult.

    But if we pull it off, I suppose we've just done a great deal of good for the Library of Congress, have we not? ;)
    ---

  • Hey, I found a online book here (Secret Signals) [btinternet.com] with loads of information, dechiffered messages and so on.

  • Over at shmoo.com, we've been running our own number station contest [shmoo.com] for over a month now. We're not using a OTP, so it is very solvable. The hard part is we have streaming audio feeds, so you actually need to do a bit of transscription. ;)

    Anyhoo, if you're interested, tune in to a number station you actually have a chance at cracking. BTW: the prize is currently 2 DVD's.
  • Salon [salon.com] had an article [salon1999.com] last year about the number stations.
    --
  • by Anonymous Coward
    Thanks to google cache!!!! You can view it at: http://realmofdarkness.org/otp/
  • some guys probably just got together and recorded this insane wino from the alley behind my house. All fucking day he goes on with this shit

    "one, four, twenty, bhgrrarg" (he usually seizures for a minute or two)"fifteen, three..."

    Sometimes he does it in french. i think he was in the war

    "quatre, dix, vingt..."


    FluX
    After 16 years, MTV has finally completed its deevolution into the shiny things network
  • There just isn't enought information to do anything but put a bunch of smart people in front of the data and see what they can figure out.

    Of course that could be the goal. If you really want to mess with the other guys, you could use a scheme like this to do it. The process would be pretty simple:

    1. Develop a decent cryptographic random number generator and have it spew out a bunch of random numbers. Even better, mix in a bunch of encrypted, realistic sounding, but bogus messages to your international spy network. Use an encryption scheme that's likely to be very tough to break, but not quite impossible.
    2. Hire a bunch of poor schlubs to read off your list of numbers into a microphone. You can save yourself some time and effort by rebroadcasting the messages several times in rapid succession; this might actually be helpful in the real world in case your agents have to transcribe the thing without aid of tape recordings.
    3. Watch as your poor enemy wastes a lot of effort trying to decode the thing. Even better, if you think that they've actually succeeded in decoding it, you can use it to sow disinformation.

    All it takes is a bit of effort: one cryptographic algorithm, a creative guy or two to write bogus messages, and a bunch of people you can hire pretty cheap to read off your lists of numbers. If you're lucky, you can tie up several capable cryptographers trying to decode it, which is probably a net win. If you're really lucky, they'll succeed, buy it hook, line, and sinker, and you can start using it to give them disinformation. Sounds like a reasonable thing to try.

  • *sigh*

    Some things are very very hard, so people name them impossible. Some things are proven to be impossible under certain assumptions. One Time Pad encryption is proven to be unbreakable assuming that the key remains secure (well d'uh), the key is truely random, and the key used once and only once. The only points of attack would seem to be either espionage (steal the key, or some variation thereof), or exploiting some weakness in the random number generator.

    Theoretically it might just barely be possible to exploit the very very small "non-randomness" of the random number generator, however I would rather bet on a computer completely solving chess than this (which, btw, is simply not possible, due to the sheer size of the solution to chess compared with the size of our universe).

  • "o...r...p...h...a...n.....a...n...n...i...e.....s ...a...y...s.....'A...l...w...a...y.. .s. ....d...r...i...n...k.....y...o...u...r......O...V ...A...L...T...I...N...E'"

    Credit goes to our top codebreaker, Ralphie.

  • 1) Get yourself elected president 2) Call the directors of the CIA and NSA into your office and ask them
  • by Roblimo ( 357 ) on Saturday May 27, 2000 @10:16AM (#1042939) Homepage Journal
    Yes, the "numbers stations" are almost certainly using one-time pads, but there are levels of obscurity they may use that go beyond that:

    1) There is no reason all the numbers broadcast 24/7 must have any meaning, so a "key" could contain instructions that tell a recipient to listen for the string "24 41 00 65" after 12:32 p.m. and that the numbers between that string and "24 41 00 56" are the message.

    2) A one-time pad usually encodes phrases, not letters or single words. A complex one can have multiple phrases available from which one can construct a complete message, ie 48 = "meet me," 47 = "at the courthouse steps," 97 = "at phillip's house," and so on. Both the numbers and the phrases can be chosen arbitrarily, and can be changed every week or even every day.

    3) The date/time key can be kept separate from the decode key; that is, which strings to listen to, and when to listen for them, can be kept as a "key book" in an embassy safe, while the number/phrase "code book" can be in the possession of a staff member who does not live or work on the premises. If someone gets hold of the key book it does them no good without the code book, and vice versa.

    This is good old-fahioned human stuff. To "decode" a message, you have to both suborn the embassy staff and find the code book. And if the person who has the code book doesn't report in, that code won't be used again, so capturing a code book does not allow you to decode future messages. Key books, too, can be changed if there is any suspicion that one has fallen into wrong hands.

    Bill Gates might be able to crack this kind of code - not with computers, but by bribing both embassy staff members and the outside people to whom the actual messages are being sent, assuming the above message-passing method is the one being used, which may not be the case.

    Humans are always the weak link. Even with "unbreakable" codes or ciphers, if the person who writes the original message is an enemy agent all the transmission security in the world won't keep it away from the enemy (or commercial competitor).

    In light of all this, if I wanted to "prove" I could crack a "number station" code, I'd bribe someone at the transmitting end to send a message with content I already knew, at a predetermined time that I also knew.

    This is not a particularly original thought, BTW. It's been used in at least a few spy novels as a way for a turncoat agent to gain a new master's trust.

    - Robin

  • I just finished "The Puzzle Palace" and "The Code Book" and I would disagree with you. There was a detailed story about a tech at GCHQ who was selling data to the East Germans. They gave him a briefcase with several years of one-time-pads, and the schedule for one of their Numbers Stations. The briefcase had a false bottom and also contained secret writing material with fake letters that he could send to a maildrop in Germany for return communication.

    Key distribution is not so much of a problem if you only intend to communicate once a week or so, and you wouldn't even have to use all those keys--just have an identifier that says "No messages for you today!"

    BTW: Sent from one of those QNX bootdisks! Fast teeheehee.

  • by KFury ( 19522 ) on Saturday May 27, 2000 @10:18AM (#1042942) Homepage
    With so many nations and agencies broadcasting number stations, some of them have to be solely for disinformation purposes.

    If these are actual encryptions are using one-time pads as keys, then a brute-force attack (ala distributed.net) would be worthless, unless they're actually using the 'one-time' pads more than once.

    What seems more approachable is taking a look at these streams of numbers, looking for the patterns inherient in random number generators. If the method of generating random numbers can be found (which really shouldn't be that hard if the 'disinformation code' is being generated by two guys in a hut and an old PC), then specific stations can be singled out as disinformation stations, sending out 'predictable' random numbers.

    Chances are that most of these stations are just that, disinformation beacons.

    On the other hand, if they're not, then there must be some header information to identify whether a given broadcast is intended for you (a specific spy) or another agent. This sort of info would likely be the first step of a decryption process, because it would be unlikely that they would force every agent to use up part of a one-time pad at every broadcast just to determine if the broadcast was for them. More likely, there would be some algorithm performed on the header, so an agent can get a reasonably certain idea if the broadcast is meant for them.

    My first guess would be something combinitorial, like multiplying the 'agent IDs' of each agent the message applies to, so the agents have only to take the header numbers and see if it's divisable by their number. If so, grab a pen and dig out your one-time pad.

    I wonder how many of these sorts of things are already on the net. It makes me want to start a page (that people should mirror, for obfuscation's sake) with random numbers that change every day. Heck, LavaRand [sgi.com] is probably doing that right now. Sure they say it's coming from lava lamps, but it could just as easily be messages to spies all over the world, and with 50,000 hits every day, who could trace each one down to find a mobile spy?

    Kevin Fox
  • Sure, you and I think, "Why bother trying to decode these if they are one-use keys?" But remember, this is the US 'intelligence' community that have no accountability for their budgets.

    Sometimes the people sending the messages screw up and make mistakes, such as distributing a pad more than once or using a defective random number generator. The NSA cracked a large number of KGB/GRU messages (see VENONA [nsa.gov]) when the Soviets ran low on one time pads and issued duplicate one time pads. The rumor is that the person responsible for this disaster was shot.

  • Wow, I didn't think anybody on slashdot would know so little about the history of computers.

    Didn't you know that computers have been around since the early 40's? The first being Colossus. It's main purpose was to decypher German cryptography.

    So, tell me why they wouldn't use computers for these sequences when 10 years previously computers had proven themselves usefull for cryptographical purposes?
  • Assuming this isn't just a giant hoax,

    This has been going on for 30 years, and it is clearly intended to be received by field agents who do not have access to heavy equipment. This is enough to know it's going to be a one time pad.

    Consider: the people running this know that their opponents have computer, have cryptographer, and have lots of time. Not knowing the algorithm will slow them down for a while, but remember that this has to be an algorithm that can be done by hand. It can't be DES. It has to be something the average spy could do in the basement. Solitaire shows that it is possible to create a secure algorithm without a computer, but it has limits (more text makes it easier to break, encrypting with the same key twice makes it trivial to break). I doubt the government came up with anything fundamentally better 30 years ago. With any of the systems, key management would probably be way to painful to be useful.

    But a one time pad is easy. Just write the nunbers on a dozen sheets of tissue paper, and it's pretty easy to hide. You won't go through the OTP very quickly either. You don't need to have every transmission have actual information. As a bonus, a one time pad is easy. All you have to do is modular arithmetic.

    So you aren't going to be able to break it. The governments made all the stupid mistakes in WWII, and they're quite competent by now.
  • Ok, first off, I don't pretend to be an expert, but I do know some things. Isn't it theoretically possible to just use random radio noise for the OTP ciphers? Maybe it would be better to tune into a bunch of similar frequencies, and then pipe 'em all through one channel, seeing as the constructive and destructive interference would chage according to wavelength and amplitude.
  • by ktakki ( 64573 ) on Saturday May 27, 2000 @10:20AM (#1042963) Homepage Journal

    Given that the telephone company does this all the time (The number you requested is ...), it's undoubtedly a recorded voice.


    But it's not. Unless they also pre-recorded sneezes and coughs, too.

    I've listened to these broadcasts since the early '80s, both the English- and Spanish-language stations. Definitely a human reading from a sheaf of papers.

    "...dos, ocho, zero, zero, cuatro...ocho, ocho, uno, zero, dos...achoo!...excusame...dos, dos, ocho, cinco, siete..."

    k.

    p.s.: The Cold War may be over, but the Cobra Dane over-the-horizon radar still drones on, too.

    --
    "In spite of everything, I still believe that people
    are really good at heart." - Anne Frank
  • by kaphka ( 50736 ) <1nv7b001@sneakemail.com> on Saturday May 27, 2000 @10:22AM (#1042964)
    D'oh! IANACE either, but I was looking forward to showing off my limited knowledge of this topic by pointing that out first. You beat me to it.

    I agree, it seems very likely that these stations are using one-time-pad encryption, particularly since the messages are so short, and (presumably) intended to be decoded by hand. I thought that was pretty common knowledge. It makes me wonder why they'd even bother... Although a thought just occurred to me: with a little imagination, I'm sure you could "decode" these broadcasts and find messages about alien abductions, government conspiracies, terrorist plots, or anything else. It's just like the "Bible Code" [csicop.org]... a modern-day Rorsarch test.
  • Hey,

    If you want my opinion, even with the entire of distributed.net's computing power, cracking this message would be impossible. Distributed.net is looking for a known message with a known algorithm at low - 64-bit - encryption. They are, at the current rate, looking at roughly 2,000 days total at the current rate. If the encryption is simply algorithmic, the keyspace of about 5 algorithms would have to be exhausted, asuming it's a publically-availiable algorithm. That would be over 10,000 days, assuming the encryption is only 64-bit. If I was doing top-secret spy communications, I would use at least 256-bit key, maybe more. That would involve literally millions of keys. Then, of course, there's the book cryptography method. That would be near-unbreakable, even if we had quickly downloadable copies of every book in existance. Or maybe it's a vernam-cipher (one-time pad) system. I doubt an entire country's inteligence budget would flinch at the cost of a hardware RNG.

    So, let's recap:

    1) We barely have the facility to crack a 64-bit message.
    2) This message could have any strength of encryption.
    3) This message could use any of a wide range of algorithms.
    4) This message could use an algorithm we don't know of.
    5) We have no way of knowing if we have managed to crack a message as we don't know the content.
    6) There could be multiple layers of encryption using varying, unknown algorithms.
    7) They may well use one-time pads.
    8) Said one-time pads cound be totaly random.

    In conclusion, cracking number-station messages could and probably would be emmensely close to impossible using today's technology, assuming the security is good, which it would almost certainly be.

    You're welcome to try, but I don't think it's possible.

    Michael

  • There's another problem. I don't have any "inside" knowledge, but I've heard that these stations, and other high security crypto broadcasts like them, are transmitting "data" all the time, even when there's no message.

    The reason for this is that if you suddenly go on the air and start broadcasting, you tip the other side that something going on. I suppose you could go off and on at "random", but that doesn't conceal as much information as just broadcasting all the time. For example, the other side could perform specific provocative acts to see if the channel would go on in response. Then, they'd know whether the given channel is to address the particular provocation.

    It may be that there is some other external source, such as a quick message on another frequency, something planted in a news report, etc., that tells the receiver when to start listening and for how long.

    The 4-cd set may have exactly no content whatsoever. It could well be just random numbers, or even more maddening a very complicated encrypted message that resolves down to a nonsense message.


    -Jordan Henderson

  • by jd ( 1658 ) <imipak@ y a hoo.com> on Saturday May 27, 2000 @11:56AM (#1042977) Homepage Journal
    Actually, we have several possible pieces of information, which could help in breaking this code. NOTE that I use the word "code", rather than cypher.

    IMHO, this is the first clue that we have. Cyphers are great for electronic or mechanical delivery, but don't work so well with the spoken word. The output isn't designed that way. Codes, on the other hand, are optimised to be spoken or written, and are often not much more than simple substitution.

    Let's assume, then, that these numbers are some kind of basic word or phrase substitution. How many numbers there are in the transmission will give you a much clearer indication of what kind of code is being used. This is the second clue. Lots of numbers = a simple meaning for each. Few numbers = a complex meaning for each.

    This brings me to the third clue. The more numbers the simpler the difference between each of the transmissions. If you've only one or two numbers, you can have some very complex operations going on but if you're using lots, then you can't. The message HAS to be decypherable in a practical length of time, BY HAND, BY A HUMAN. Humans are not designed to be memory gurus.

    Now for the final clue. The messages have been sent since the 1950's. This was at the height of Cold War paranoia. At that time, I doubt anybody in an intelligence agency would have trusted short wave radio -that- much. Too unreliable, especially over the distances that would be implicitly involved.

    But the military weren't the only ones gripped in psychotic paranoia, gun-fever and a cult-like power craze. Most of America was (and is) gripped in exactly the same delusion.

    Now, short-wave radio to communicate between gun cults is entirely believable. Far more so than to believe the CIA or whoever would care for such primitive tools.

    IMHO, it's more likely a splinter faction of the NRA than the CIA. More believable still is that it is groups of survivalists, trying to avoid Government mind-control rays with tin-foil helmets and earthed pick-ups (with the obligatory dog in the back).

    The most extreme possibility I can think of, which remains plausable, is that some survivalists have convinced themselves that World War 3 happened in the 1950's, and that all evidence to the contrary is an enemy plot to lure them out from their shelters. (Sufficiently isolated areas, and leaders every bit as charismatic as David Koresh -might- be able to pull that kind of stunt off. Those Dr Who fans in the audience might also like to re-read "Enemy of the World".)

  • by kms1 ( 23201 ) on Saturday May 27, 2000 @12:04PM (#1042978)

    This page has pictures of what they claim are the one time pads taken from captured foreign agents. They were hidden in hollowed out bars of soap and talcum powder containers.

    http://www.btinternet.com/~simon .mason/page30.html [btinternet.com]

    -kms1

  • by XNormal ( 8617 ) on Saturday May 27, 2000 @12:08PM (#1042979) Homepage
    is that the numbers are really random - they are simply channelsquatting. The HF spectrum is an expensive resource because it's quite narrow and it propagates to such long distances. If you want to ensure you have your channel when you really need it just keep it busy. It's not that different than cybersquatting except that it's harder to argue with a foreign government and a few kilowatts of RF power.

    ----
  • involves a scanner buff who moved to a rural district whose police dept scrambled transmissions. Not to be left out he bought, at great expense, a voice de-scrambler and got it all installed and the first intercept he taped and played it back thru the device and was finally able to clearly hear, "Chief, did you say you wanted mustard on that pastromi sandwich?"

    Seriously, numbers stations sound like a great way to get messages to foreign operatives 'behind enemy lines', all you need is a common shortwave set, your one time pad and lots of patience - no phone lines to trace or tap, no microfilm to hide or lose, no contacts to verify, you get and decode the signals in private, the source is verified and can't be easily 'spoofed', etc.
  • by Anonymous Coward
    You covered this [slashdot.org] last September.
  • If this is indeed a one-time pad as most of the people who have studied these codes think, we might as well save our breath to cool our porridge.

    Perhaps traffic analysis might be a more fruitful approach. Of course, as Schneider pointed out on the show, we know who's sending, but we don't know who's listening :-(
  • Given that the telephone company does this all the time (The number you requested is ...), it's undoubtedly a recorded voice.
  • The first set of paragraphs on the web page state "If it is true that an 'OTP' cypher is being used in a Numbers Station transmission, then you had better read this [clark.net]."

    ...Only, http://www.clark.net/pub/mjr/pubs/otpfaq/ does not exist and produces a 404. Someone is out there destroying the information needed to pin the bastards down! I bet it is part of that one world order thingy that I've been hearing so much about!
    ---
    icq:2057699
    seumas.com

  • This cryptographic challenge is more daunting than the RSA challenge, because nothing is known about the algorithm used to encipher LP transmissions. We do not even know for sure who the transmitting party is.
    http://www.ibmpcug.co.uk/%7Eirdial/E 3crack.htm [ibmpcug.co.uk]

    Someone needs to have an insight as to a useful crypanalytic attack, to use all that hardware.

  • I would guess that these numbers form a really long one-time-pad. The agents using them pick a starting point and then XOR (or add mod 10) their message with the stream of digits. Then they only have to transmit their starting point in a complicated cipher. The agents only have to listen to the radio to get the sequence from their selected starting point, and home base either records the whole thing or has the script.

    There might be an interesting pattern in the numbers if the random number generator is only pseudo-random, but I would guess they'd use a physical process instead of a mathematical one, given that the indend to send out digits for years on end.
  • You are confusing "security through secrecy"
    with "security through obscurity".

    One works, one doesn't.
  • by Greyfox ( 87712 ) on Saturday May 27, 2000 @12:19PM (#1043008) Homepage Journal
    Why not triangulate one of these stations, go there, and ask the guy what the hell he thinks he's doing?
  • What if there are broadcast that REALLY are total bogus, just to confuse people that want to decypher it?

    Maybe the bogus-broadcasts can be destinguished from the rest through the different speakers...

    Who knows?
  • The story links to the NSA's Venona.html (which is missing, too. Google cache has it:http://www.google.com/search?q=cache:www.nsa.go v/museum/venona.html+venona+project +nsa&hl=en [google.com].

    I love Google!

  • by rjamestaylor ( 117847 ) <rjamestaylor@gmail.com> on Saturday May 27, 2000 @12:30PM (#1043016) Journal
    NSA's site is up (different link):

    here [nsa.gov].

  • by djweis ( 4792 ) on Saturday May 27, 2000 @09:00AM (#1043019) Homepage
    "Thanks for cracking the code! Your prize is a bullet in the head from a black helicopter in your back yard."
  • by The Infamous TommyD ( 21616 ) on Saturday May 27, 2000 @09:02AM (#1043020)
    Well, IANACEBIHTGC. (I am not a crypto expert but I've had two graduate classes. In cryptographic protocols and advanced cryptanalysis.
    These strings of numbers are very likely to be from a one time pad which given certain assumptions are fundamentally unbreakable. The assumptions are: you never lose the pad (codebook), you never reuse the pad, the pad is truly cryptographically random. The proof of this is fundamental information theory.

    If they are not one time pads, then it is possible, but a brute force attack like distributed net only works when you know the algorithm or the general family of them anyway. Also, it helps alot if you know something of the plaintext that you're after. If say, the number stations are transmitting encrypted random data such as the encryption keys for other other communications, then how the hell would you know that you'd found something when you decrypted it.

    There just isn't enought information to do anything but put a bunch of smart people in front of the data and see what they can figure out.
  • by Anonymous Coward on Saturday May 27, 2000 @09:02AM (#1043021)
    break it. It's a one time pad. The following string:

    a8dmldk38f7ekal3973jdm43kaeqq

    could be either:

    my hovercraft is full of eels

    or:

    Hello, I love Natalie Portman

    or a million other phrases that fit within the length limitation.

  • Humor ... I think ...
    I notice they don't describe the prize, and require: All email concerning this challenge must be PGP encrypted.

    I wonder just how wise it would be to try to claim victory:

    "Thank you for telling us you broke this supersecret code. And thanks for proving your identity with PGP. Please remain where you are, our representatives will arrive shortly with your reward ..."
  • by Signal 11 ( 7608 ) on Saturday May 27, 2000 @09:03AM (#1043026)
    Personally, I can't wait until the NSA has its own IPO - what, with all the demand for privacy-invading software and hardware, employers spying on employee e-mail and phone calls. I'd daresay it might even fund Echelon II ("This time, it's really, really personal").
  • by Alik ( 81811 ) on Saturday May 27, 2000 @09:04AM (#1043028)
    I honestly don't see how someone could hope to succeed at this. Let's say you get distributed.net to jump on the bandwagon. Great. Now what exactly are you going to do? You have arbitrary strings of numbers. This could be a fragment of a single text, parts of multiple texts, multiple complete texts, and so on. Sure, you could scan for patterns first and try to identify delimiters, but were I sending data through this, I wouldn't do you the favor of using a fixed separation string. I'd base it on conditions at the time of broadcast, or on some computation on the ciphertext, or some other thing that's not trivially detectable. In short, you don't know which decryption method to try. It's been pointed out that it's probably a one-time pad anyway.

    Even if you can find an algorithm, how big are the keys? How will you know when you've got the plaintext? Something transmitted by the NSA is likely to be in highly obfuscated English at best. Like the handmade strong crypto [jdueck.org] challenge, the true plaintext might be very strange. How will you recognize that this is the correct decryption and not just a coincidental decryption into random gibberish?

    Finally, while I agree that some numbers stations probably are espionage related, I'll bet they keep the noise very high. Many of them are probably reading right off the random number generator of the nearest computer. Did the challenge supervisors pick ones that are actual signal?

    This is not to say it's impossible, but the benefit/difficulty ratio seems so high that anybody wizardly enough to succeed should probably be working on developing better algorithms for us instead.
  • > I would guess that these numbers form a really long one-time-pad.

    Actually, if you subtract four from each number in the sequence, you will immediately see that they are just calling out the /. moderation scores on the previous day's comments.

    --
  • Chances are it is a one-time pad, but not necessarily one you do XOR math on, or indeed one where you do any math at all. It is a code book, and a short one at that.

    Spies have to conceal stuff; you can't have a book called How To Decrypt Your CIA Messages in your backpack all the time. So the codes would be simple and there would only be a handful of them. So few, in fact, that you could memorize them.

    If I had to guess (and this is Slashdot so rampant speculation is practically a mandate), I would say that 99.999% of what's transmitted from numbers stations is steganographic white noise and that each agent has only three or four codes of five or so digits to memorize, and that there are rules like "if your message contains a number that begins and ends in sevens, this message is bogus, unless the inner three digits sum up even". The three or four messages to pay attention to would be "pick up instructions at dead drop one/two/three", "meet your handler in person at rendezvous point one/two/three", "suspend all spy activities until further notice", and "get out now." And when they pick up a new set of instructions, there may be an update to the code list, to keep transmissions as unrepeating as possible.

    A technique like this has a lot of advantages. First, the list of messages is short enough to memorize, so there is one less piece of damning evidence lying around the house. Second, it delegates the important, detailed spy stuff to more conventional field communication techniques.

    Finally, it dramatically reduces the risk of having real messages discovered. One of the greatest risks of spying is discovery when picking up or retreiving messages from handlers. Now, instead of sitting waiting on a park bench every Tuesday at noon to see if a man with a red shopping bag goes by, you just put a tiny radio in your ear while you take your Tuesday shower and keep your ear cocked for a couple of memorized key codes.

    Spy work is often rather slow-paced; except for emergencies, field agents' instructions probably don't need updating more than every couple of months. Picking a meaningful single five-digit string out of two months worth of meaningless five-digit strings is probably well beyond the capabilities of mere mortals.

    --

  • So what is going on here. This is the first time I've ever heard of this and I must say that it is totally amazing. But what are things like from a 17yo geek's point of view? Well here are just a few things to ponder: 1. First of all because they broadcast (mostly) 24/7, they obviously have a computer with samples for each number/etc (1.wav, 2.wav....) so why does one person have to sit there recording it? Can't a computer be taught to listen and compare the samples to get the numbers for us? The samples never change (for a given station) so why not? 2. Not only are the codes probably one time only, but how do we know what language they are meant for? Just because a station's voice is in French doesn't mean the data is in English, Pig-Latin, or a totally invented language that is not natively spoken anywhere. It could even be a language that is now dead and was never recorded. If an old computer of sort is doing this stuff automatically, what's to say that any of it is still readable? 3. Has anyone compared the numbers being listed from different stations at the same time (say midnight GMT), or at the same time local (like 5pm from wherever the station is broadcasting) to see if they are the same? Maybe you must do something with the different sequences from multiple stations (such as XORing). 4. Do the numbers go to a certain range? Do they stop at 8? 32? 109324? Maybe if the base isn't 10 then converting it would cause it to make much more sense. 5. Who says the numbers represent words/letters? What if the represent syllables? What if it depends on the hour you tune in? Maybe the letters/words/syllables are reversed! Or alternating? 6. What is the prize? Simple! You'll be world famous for being the geek who cracked what might possibly be the world's most pointless code (see below). Maybe it's a subliminal message. 7. What could it possibly say? Good question! What if it's just variations of "Drink Coca-Cola all the time" or even something as out-dated as "Cure the flu with a Marlboro or two!" There are just points to ponder. Have fun!
  • by cosmicaug ( 150534 ) on Saturday May 27, 2000 @12:48PM (#1043039)
    Of course they are intelligence broadcasts. That has been known for a long time. What has not been known until this day is that it is not crypto. They are just playing Bingo [vic.gov.au]
  • The message is encoded into numbers before it is encrypted and transmitted. Here is an example of an encoding table:

    0 1 2 3 4 5 6
    S N E G O P A
    7 B C D F H I J
    8 K L M Q R T U
    9 V W X Y Z / .

    The letters on the first line (S N E G O P A) are encoding to the single digits 0 through 6. The letters on the second, third and fourth lines are encoded to double digit numbers. For example:

    F = 73
    I = 75
    R = 84
    S = 0
    T = 85

    P = 5
    O = 4
    S = 0
    T = 85

    In code groups:

    73758 40855 4085X

    (X indicates null padding to fill last group)

  • Unfortunately, it takes approximately four years to download one single.
  • Knowing the US government's penchant for doing things in the most expensive way possible, it is not inconcievable that other nations could be using numbers stations as a very cheap way to tie up resources at US intelligence agencies. Think about it - supercomputers are spendy, crypto experts are spendy, coming up with a random bunch of numbers and broadcasting them over shortwave is incredibly cheap. So, I can immagine that for every dollar Cuba spends on numbers broadcasts, the US spends 1000 or even 10,000 times that to track and (try to?) decode the transmitions. Sure, you and I think, "Why bother trying to decode these if they are one-use keys?" But remember, this is the US 'intelligence' community that have no accountability for their budgets.
  • It is technically possible to break the encryption of one-time pads. A process for it is described in Cryptonomicon by Neal Stephenson (which is a damn good book). All one has to do is realize that the pads numbers can not be purely random. There must be some sort of algorithm or person generating the pseudorandom numbers. Figure out the key to this and you can crack parts of some of the pads generated using this algorithm.
    ______________________________________ _________________
  • by Anonymous Coward on Saturday May 27, 2000 @09:07AM (#1043049)
    These are not broadcasts used by intelligence agencies, they're from ordinary people trying to beat the world record of "reciting the digits of Pi on radio".

    You fool! You see global conspiracy everywhere!

  • I've been thrilled by the mystery of numbers stations since I was a young'un. I think it's the simplicty that makes them so fascinating. So many conspiracy theories and supernatural phemonena (crop circles, alien abductions, JFK, etc.) are complex and full of half-truths and hoaxes.

    Numbers stations are so simple, elegant, yet mysterious. (Therefore mysterious?) You can have any theory that you want (and they're all probably far more interesting than the truth), and there's little evidence on way or the other.

    I only discovered The Conet Project [ibmpcug.co.uk] through /. a few months ago, but I think they're great. It takes a lot of time to study this kind of stuff, with no likely returns from the work.

    Like I said, useless post. :) But at least I'm posting at 1 instead of 2...

    -Waldo
  • No, they did not.

    They covered the fact that this was a possibility. Now that they are ready for a crack attempt, they are letting the readers know. I believe when I read that last story, they just discussed WHAT they wanted to do. Now it's ready.

    -S

    Scott Ruttencutter

Get hold of portable property. -- Charles Dickens, "Great Expectations"

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